Beginner to the fullest

Just purchased my first mountain bike, basically to use as a weekend-roamer when camping and to use at the local state parks.

I wasn't in need of anything extremely fancy. To be honest, a department store bike would fit me just fine but I would rather purchase local so I went with a 2014 Specialized Hardrock 26 from my lbs.

Taking it on the local trails has been an absolute blast, can't get enough of it! Down the road, I would like to do some small upgrades here and there which is the reason for the post.

I know I should have splurged and spent an extra hundred or so on the SE Disc, but it is what it is. The current brakes for my level suite me just fine.

If I were to replace the fork, what would be my options without having to replace the tires and whatnot? Also, if I were to go with disc brakes down the road, would it be a viable option on my current bike?

Thanks for any assistance, just looking for some general info!

Edit: I should also state i'm 5'11' 180 pounds, and general riding will be trails (roots, rocks, ect.. small drops, and I mean very small)...so much fun!

Rock Shox has 26" forks in several levels and price ranges, all disc compatible. Specialized says your frame has a caliper hanger, so your good to go to convert if you wanted.
If I were you though, I'd ride it as it is while working on base fitness and skills, then when the time comes for upgrades, sell it and get another bike with all the stuff on it that you wished you had on this one.